Collaboration diagram for XXH32 family:

Classes
struct	XXH32_canonical_t
	Canonical (big endian) representation of XXH32_hash_t. More...

Macros
#define	XXH32_createState(void) XXH_NAME2(XXH_NAMESPACE, XXH32_createState)
	Allocates an XXH32_state_t. More...

#define	XXH32_state_t XXH_IPREF(XXH32_state_t)
	The opaque state struct for the XXH32 streaming API. More...

#define	XXH_FALLTHROUGH

#define	XXH_HAS_ATTRIBUTE(x) __has_attribute(x)

#define	XXH_HAS_C_ATTRIBUTE(x) 0

#define	XXH_HAS_CPP_ATTRIBUTE(x) 0

Typedefs
typedef struct XXH32_state_s	XXH32_state_t

Functions
XXH_PUBLIC_API XXH32_hash_t	XXH32 (const void *input, size_t length, XXH32_hash_t seed)
	Calculates the 32-bit hash of `input` using xxHash32. More...

XXH_PUBLIC_API void	XXH32_canonicalFromHash (XXH32_canonical_t *dst, XXH32_hash_t hash)
	Converts an XXH32_hash_t to a big endian XXH32_canonical_t. More...

XXH_PUBLIC_API void	XXH32_copyState (XXH32_state_t dst_state, const XXH32_state_t src_state)
	Copies one XXH32_state_t to another. More...

XXH_PUBLIC_API XXH32_hash_t	XXH32_digest (const XXH32_state_t *statePtr)
	Returns the calculated hash value from an XXH32_state_t. More...

XXH_PUBLIC_API XXH_errorcode	XXH32_freeState (XXH32_state_t *statePtr)
	Frees an XXH32_state_t. More...

XXH_PUBLIC_API XXH32_hash_t	XXH32_hashFromCanonical (const XXH32_canonical_t *src)
	Converts an XXH32_canonical_t to a native XXH32_hash_t. More...

XXH_PUBLIC_API XXH_errorcode	XXH32_reset (XXH32_state_t *statePtr, XXH32_hash_t seed)
	Resets an XXH32_state_t to begin a new hash. More...

XXH_PUBLIC_API XXH_errorcode	XXH32_update (XXH32_state_t statePtr, const void input, size_t length)
	Consumes a block of `input` to an XXH32_state_t. More...

Detailed Description

Contains functions used in the classic 32-bit xxHash algorithm.

Note: XXH32 is useful for older platforms, with no or poor 64-bit performance. Note that xxh3_family provides competitive speed for both 32-bit and 64-bit systems, and offers true 64/128 bit hash results.

See also: XXH64 family, xxh3_family : Other xxHash families; XXH32 implementation for implementation details

Macro Definition Documentation

◆ XXH32_createState

XXH_PUBLIC_API XXH32_state_t * XXH32_createState XXH_NAME2(XXH_NAMESPACE, XXH32_createState)

Allocates an XXH32_state_t.

Must be freed with XXH32_freeState().

Returns: An allocated XXH32_state_t on success, NULL on failure.

Definition at line 7034 of file zstd.c.

◆ XXH32_state_t

struct XXH32_state_s XXH32_state_t XXH_IPREF(XXH32_state_t)

The opaque state struct for the XXH32 streaming API.

Streaming functions generate the xxHash value from an incremental input. This method is slower than single-call functions, due to state management. For small inputs, prefer XXH32() and XXH64(), which are better optimized.

An XXH state must first be allocated using XXH*_createState().

Start a new hash by initializing the state with a seed using XXH*_reset().

Then, feed the hash state by calling XXH*_update() as many times as necessary.

The function returns an error code, with 0 meaning OK, and any other value meaning there is an error.

Finally, a hash value can be produced anytime, by using XXH*_digest(). This function returns the nn-bits hash as an int or long long.

It's still possible to continue inserting input into the hash state after a digest, and generate new hash values later on by invoking XXH*_digest().

When done, release the state using XXH*_freeState().

Example code for incrementally hashing a file:

#include <stdio.h>
#include <xxhash.h>
#define BUFFER_SIZE 256
 
// Note: XXH64 and XXH3 use the same interface.
XXH32_hash_t
hashFile(FILE* stream)
{
    XXH32_state_t* state;
    unsigned char buf[BUFFER_SIZE];
    size_t amt;
    XXH32_hash_t hash;
 
    state = XXH32_createState();       // Create a state
    assert(state != NULL);             // Error check here
    XXH32_reset(state, 0xbaad5eed);    // Reset state with our seed
    while ((amt = fread(buf, 1, sizeof(buf), stream)) != 0) {
        XXH32_update(state, buf, amt); // Hash the file in chunks
    }
    hash = XXH32_digest(state);        // Finalize the hash
    XXH32_freeState(state);            // Clean up
    return hash;
}

See also: XXH32_state_s for details.

◆ XXH_FALLTHROUGH

#define XXH_FALLTHROUGH

Definition at line 5545 of file zstd.c.

◆ XXH_HAS_ATTRIBUTE

#define XXH_HAS_ATTRIBUTE ( x ) __has_attribute(x)

Definition at line 5514 of file zstd.c.

◆ XXH_HAS_C_ATTRIBUTE

#define XXH_HAS_C_ATTRIBUTE ( x ) 0

Definition at line 5523 of file zstd.c.

◆ XXH_HAS_CPP_ATTRIBUTE

#define XXH_HAS_CPP_ATTRIBUTE ( x ) 0

Definition at line 5529 of file zstd.c.

Typedef Documentation

◆ XXH32_state_t

typedef struct XXH32_state_s XXH32_state_t

Definition at line 5383 of file zstd.c.

Function Documentation

◆ XXH32()

XXH_PUBLIC_API XXH32_hash_t XXH32	(	const void *	input,
		size_t	length,
		XXH32_hash_t	seed
	)

Calculates the 32-bit hash of input using xxHash32.

Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark): 5.4 GB/s

Parameters

input	The block of data to be hashed, at least `length` bytes in size.
length	The length of `input`, in bytes.
seed	The 32-bit seed to alter the hash's output predictably.

Precondition: The memory between input and input + length must be valid, readable, contiguous memory. However, if length is 0, input may be NULL. In C++, this also must be TriviallyCopyable.

Returns: The calculated 32-bit hash value.

See also: XXH64(), XXH3_64bits_withSeed(), XXH3_128bits_withSeed(), XXH128(): Direct equivalents for the other variants of xxHash.; XXH32_createState(), XXH32_update(), XXH32_digest(): Streaming version.

Definition at line 7010 of file zstd.c.

◆ XXH32_canonicalFromHash()

XXH_PUBLIC_API void XXH32_canonicalFromHash	(	XXH32_canonical_t *	dst,
		XXH32_hash_t	hash
	)

Converts an XXH32_hash_t to a big endian XXH32_canonical_t.

Parameters

dst	The XXH32_canonical_t pointer to be stored to.
hash	The XXH32_hash_t to be converted.

Precondition: dst must not be NULL.

The default return values from XXH functions are unsigned 32 and 64 bit integers.

The canonical representation uses big endian convention, the same convention as human-readable numbers (large digits first).

This way, hash values can be written into a file or buffer, remaining comparable across different systems.

The following functions allow transformation of hash values to and from their canonical format.

Definition at line 7155 of file zstd.c.

◆ XXH32_copyState()

XXH_PUBLIC_API void XXH32_copyState	(	XXH32_state_t *	dst_state,
		const XXH32_state_t *	src_state
	)

Copies one XXH32_state_t to another.

Parameters

dst_state	The state to copy to.
src_state	The state to copy from.

Precondition: dst_state and src_state must not be NULL and must not overlap.

Definition at line 7046 of file zstd.c.

◆ XXH32_digest()

XXH_PUBLIC_API XXH32_hash_t XXH32_digest ( const XXH32_state_t * statePtr )

Returns the calculated hash value from an XXH32_state_t.

Note: Calling XXH32_digest() will not affect statePtr, so you can update, digest, and update again.

Parameters

statePtr The state struct to calculate the hash from.

Precondition: statePtr must not be NULL.

Returns: The calculated xxHash32 value from that state.

Definition at line 7120 of file zstd.c.

◆ XXH32_freeState()

XXH_PUBLIC_API XXH_errorcode XXH32_freeState ( XXH32_state_t * statePtr )

Frees an XXH32_state_t.

Must be allocated with XXH32_createState().

Parameters

statePtr A pointer to an XXH32_state_t allocated with XXH32_createState().

Returns: XXH_OK.

Definition at line 7039 of file zstd.c.

◆ XXH32_hashFromCanonical()

XXH_PUBLIC_API XXH32_hash_t XXH32_hashFromCanonical ( const XXH32_canonical_t * src )

Converts an XXH32_canonical_t to a native XXH32_hash_t.

Parameters

src	The XXH32_canonical_t to convert.

Precondition: src must not be NULL.

Returns: The converted hash.

Definition at line 7162 of file zstd.c.

◆ XXH32_reset()

XXH_PUBLIC_API XXH_errorcode XXH32_reset	(	XXH32_state_t *	statePtr,
		XXH32_hash_t	seed
	)

Resets an XXH32_state_t to begin a new hash.

This function resets and seeds a state. Call it before XXH32_update().

Parameters

statePtr	The state struct to reset.
seed	The 32-bit seed to alter the hash result predictably.

Precondition: statePtr must not be NULL.

Returns: XXH_OK on success, XXH_ERROR on failure.

Definition at line 7052 of file zstd.c.

◆ XXH32_update()

XXH_PUBLIC_API XXH_errorcode XXH32_update	(	XXH32_state_t *	statePtr,
		const void *	input,
		size_t	length
	)

Consumes a block of input to an XXH32_state_t.

Call this to incrementally consume blocks of data.

Parameters

statePtr	The state struct to update.
input	The block of data to be hashed, at least `length` bytes in size.
length	The length of `input`, in bytes.

Precondition: statePtr must not be NULL.; The memory between input and input + length must be valid, readable, contiguous memory. However, if length is 0, input may be NULL. In C++, this also must be TriviallyCopyable.

Returns: XXH_OK on success, XXH_ERROR on failure.

Definition at line 7066 of file zstd.c.

Classes

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ XXH32_createState

◆ XXH32_state_t

◆ XXH_FALLTHROUGH

◆ XXH_HAS_ATTRIBUTE

◆ XXH_HAS_C_ATTRIBUTE

◆ XXH_HAS_CPP_ATTRIBUTE

Typedef Documentation

◆ XXH32_state_t

Function Documentation

◆ XXH32()

◆ XXH32_canonicalFromHash()

◆ XXH32_copyState()

◆ XXH32_digest()

◆ XXH32_freeState()

◆ XXH32_hashFromCanonical()

◆ XXH32_reset()

◆ XXH32_update()